T~p<br />
<br />
chi CO' h9c<br />
<br />
Journal of Mechanics, NCNST of Vietnam T. XVII, 1995, No 1 (15- 21)<br />
<br />
ONDINH CUA BAN MONG THEQLYTHUYET QUA TRINH<br />
•<br />
<br />
'<br />
<br />
X<br />
<br />
>,<br />
<br />
'<br />
<br />
><br />
<br />
-<br />
<br />
/'<br />
<br />
-<br />
<br />
. , :•<br />
<br />
-~-'<br />
<br />
···:<br />
<br />
r<br />
<br />
'<br />
<br />
_.<br />
<br />
',~<br />
<br />
•<br />
<br />
""<br />
<br />
BIEN DANG DAN DEO V:QI VAT<br />
<br />
,.<br />
<br />
""<br />
<br />
LI~U<br />
<br />
,<br />
<br />
NEN DUQ'C<br />
<br />
DAo VAN DUNG<br />
<br />
ae<br />
<br />
Va:n<br />
5n d!nh cda bin din 4l!o ch}u qui trlnh tii ph tfc t~p dOi v&i v~t li~u khOng n€n drrgc<br />
dfi drrgc nghiep· ctru trbng·.: [2, 4]. Bai nay nh~m xiy dvng h~ cic ph1.rong trlnh cho bai toin 5n<br />
d!nh_dan deo .~Ua_ bAn mOng· ch}u' qui. trinh tii phiTc t~p, dOi v&i v~t li~u nen dU'qc, dOng thCri xet<br />
vi dv: pin b! nep. thea m9t ph1.rang. Tir h~ thli-c chung di cho c6 th~ nh~n 1~ cic ke't qui dOi v&i<br />
b3.n da~.r;teo v&i v~t li~u khOng nen drrqc [2, 4], ho~c bin din d~o nen drrqc khi d~t tii don giin<br />
[3], ho~c bin dim h'Oi nen drrc;rc [3].<br />
<br />
'<br />
<br />
~<br />
<br />
'<br />
<br />
1. BAI TOAN ON<br />
<br />
D~NH<br />
<br />
Xet bin m6ng ch-fr nh%t qmh a, b, chi~u diy h. V~t li~u hl nen drrvc. Dll'a vio h~ t9a d? De<br />
cic vuOng g6c ox 1 x2z sao cho tr-~c ox1, ox 2 n~m trong m~t phlng trung blnh ella bful, tr~c oz<br />
vuOng g6c v&i m~t phing niy. Gii s"li- ke't ciu chju tic d~ng ella cic hyc ngoii Pii thay dbi tliy Y<br />
theo mi}t tham sO tii t nio diy. Vin d~ d~t ra Ia xic d!nh gii tr! t&i h~n t,._ va tu·ang U·ng 13 cic<br />
ll!c t&i h~n Pii sao cho khi vrrqt ·qui cic gii tri niy thl ke't cau bi mit 6n d!nh.<br />
D~ giii bii to